There are frequently used, especially in motor vehicles, interior covering elements comprising a visible flexible outer skin, an internal support member, and a foam disposed between the skin and the support. Such elements are produced by a closed-mould foaming process, which comprises introducing a fluid material through a nozzle of the mould.
There is already known, according to document U.S. Pat. No. 5,017,115, a method for producing an interior covering element having a visible flexible outer skin, an internal support member formed by a rigid frame, and a foam disposed between the skin and a rear face at which the foam is visible, the rigid frame being fully enclosed between the skin and the foam. The rigid support frame, which is remote from a nozzle for introduction of the fluid material during moulding of the element, is held by a catch device during the moulding operation so that it remains in contact with the skin. Catching is effected in a position remote from the nozzle for introduction of the fluid material.
The invention relates to a different type of interior covering element, in which the visible flexible outer skin and the rigid internal support, which is sometimes called an “insert”, together delimit the whole of the cavity in which the foam is located, the foam accordingly not being visible anywhere, except perhaps very locally at an orifice, formed in the support, for introduction of the foaming material. Such elements are produced by a closed-mould foaming process in which the foaming cavity is delimited wholly by the skin and the support and not by a mould.
It has been noted that some interior covering elements so produced have a defect in their appearance in the form of a hollow opposite the location of the orifice for introduction of the foaming material into the support. It was then realised that, on introduction of the fluid foaming material through the orifice adjacent to one mould part, the internal support tends to come away from that mould part. At the end of the introduction, the rigid support tends to assume its original position again and therefore to form a hollow which is visible from the flexible skin side.
It would be possible to provide strong reinforcing ribs around the whole of the orifice in order to prevent the support from being lifted relative to the associated mould part. However, if the part next to the introduction orifice is extensive, the ribs must be very extensive, and they then increase the weight, and therefore the cost, of the rigid support considerably.